An inpatient program with selected overnight stays, for childhood and adolescent neuropsychiatric disorders is ongoing. The condition currently under study is that of hyperactive children (HAC). Pharmacological compounds under study in these disorders include methylphenidate, amphetamine, piribedil, L-dopa, tryptophan, Mianserin, and clorgyline. Piribedil is safe but clinically ineffective in HAC. L-dopa is minimally clinically effective in HAC. Pharmacokinetic studies with clinical responses are included. Amphetamine half-life in children is about one-third that of adults. Behavior and motor activity responses to d-amphetamine occur during the absorption phase as determined by serial plasma amphetamine following a single dose. Central neurotransmitters and their metabolities are being studied in plasma and urine. Urinary 3-methoxy-4-hydroxyphenylglycol shows a time-related decrease during treatment with d-amphetamine; homovanillic acid is unchanged. In general, norepinephrine metabolites in urine are decreased after two weeks of d-amphetamine vs. placebo and dopamine metabolites are not. Tyramine and its metabolites are also decreased following d-amphetamine, whereas phenylethylamine is greatly increased following d-amphetamine.